Apparatus for analyte examination

ABSTRACT

An apparatus comprises a biosensor disk structure including a first substrate with a first inner surface, a second substrate with a second inner surface facing oppositely toward the first inner surface, and fluidic channels reaching between the first and second inner surfaces; wherein the first inner surface has binding sites and non-binding sites adjoining the binding sites, the first substrate is transparent at the non-binding sites, and the non-binding sites have discrete polygonal configurations of equal size and shape; and the second inner surface has non-reflective areas and reflective areas bounded by the non-reflective areas, and the reflective areas have discrete polygonal configurations sized and shaped equally with the non-binding sites such that the reflective areas are located coextensively opposite the non-binding sites.

RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.14/722,652, filed on May 27, 2015 and titled APPARATUS FOR ANALYTEEXAMINATION; which is a division of U.S. patent application Ser. No.14/688,331, filed on Apr. 16, 2015, also titled APPARATUS FOR ANALYTEEXAMINATION.

BACKGROUND

In the prior art, as shown for example in U.S. Pat. No. 8,735,846, abiosensor disk may have a spiral data path encoded with digital data.The data is established by a sequence of pits and lands on the surfaceof the disk. As the disk is rotated in a reading system, light from alaser or light emitting diode is directed onto the disk at the spiraldata path. The system reads the encoded data as indicated by the lightreflected from the pits and lands.

The disk further has detector chambers for containing analytes. Ligandsare provided to bind specific analytes in place within the chambers. Thedetector chambers are interposed between the reader system and thespiral data path such that analytes in the chambers can obscure thetransmission alight to and from the data path. Accordingly, alterationsin the data read by the system indicate the presence of the specificanalytes corresponding to the ligands in the chambers where the datapath is obscured.

SUMMARY

An apparatus comprises a biosensor disk structure including a firstsubstrate with a first inner surface, a second substrate with a secondinner surface facing oppositely toward the first inner surface, andfluidic channels reaching between the first and second inner surfaces.The first inner surface has binding sites, and has non-binding sitesadjoining the binding sites. The first substrate is transparent at thenon-binding sites. The second inner surface has non-reflective areas,and has reflective areas adjoining the non-reflective areas. Thereflective areas are located opposite the non-binding sites and havediscrete polygonal configurations of equal size and shape.

In a preferred embodiment, the non-binding sites have discrete polygonalconfigurations that are sized and shaped equally with the reflectiveareas. The reflective areas are thus located coextensively opposite thenon-binding sites.

Further regarding the preferred embodiment, the reflective andnon-reflective areas are located in an assay region of the second innersurface, and the second inner surface further has a non-reflectivespectral sensor discharge region circumferentially adjacent to the assayregion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an apparatus including a biosensor diskand a system for examining a sample on the disk.

FIG. 2 is a side view of a part of the disk shown in FIG. 1.

FIG. 3 is an exploded sectional view of parts of the disk of FIG. 1.

FIG. 4 is a view taken on line 4-4 of FIG. 3.

FIG. 5 is a side view of another part of the disk of FIG. 1.

FIG. 6 is a view taken on line 6-6 of FIG. 3.

FIG. 7 is a view similar to FIG. 6 showing sample units for examinationon the disk.

FIG. 8 is a view similar to FIG. 7 showing an image of a sample unit onthe disk.

FIG. 9 is a view similar but opposite to the view of FIG. 8.

FIG. 10 is a view showing an image of another sample unit on the disk.

FIG. 11 is a view similar but opposite to the view of FIG. 10.

FIG. 12 is a view showing an image of yet another sample unit on thedisk.

FIG. 13 is a view similar to FIG. 12 but shows an image formed withlight of a differing wavelength.

DETAILED DESCRIPTION

The apparatus shown in the drawings has parts that are examples of theelements recited in the apparatus claims. These examples are describedhere to provide enablement and best mode without imposing limitationsthat are not recited in the claims.

As shown schematically in FIG. 1, an apparatus includes a biosensor disk10 and a system 20 for examining a sample on the disk 10. The parts ofthe disk 10 that are shown in FIG. 1 include a detection substrate 30and a reflection substrate 32. Discrete units 35 of the sample, whichcontains biological or other analytes, are distributed within the disk10 between the detection substrate 30 and the reflection substrate 32.The detection substrate 30 is transparent as needed for the sample units35, when viewed from that side of the disk 10, to be visible on abackground at the reflection substrate 32.

The parts of the system 20 in the example of FIG. 1 include a liquidcrystal display (LCD) panel 40, a condenser lens 42, and a sensor array46. In operation, the disk 10 rotates in its plane above the LCD panel40. The LCD panel 40 emits light in a band of wavelengths. The condenserlens 42 condenses the emitted light into a spot of greaterelectromagnetic intensity comprised of the multiple wavelengths in theband, and directs it to the disk 10. Light reflected from the disk 10reaches the sensor array 46.

As a sample unit 35 on the rotating disk 10 moves across the path oflight shown in the drawing, a processor 48 forms one or more images ofthe sample unit 35 on the background of the reflection substrate 32. Byconsidering parameters such as size, shape and position of the sampleunit 35 relative to the background in the images, the processor 48 cancorrelate those parameters with corresponding parameters of a referencesubstance, and can thus determine a degree of identity between thesample unit 35 and the reference substance. By comparing images formedat differing wavelengths, the processor 48 can compare the spectralresponse of the sample unit 35 with a known spectral response of thereference substance at the differing wavelengths, and can thus determinea further degree of identity between the sample unit 35 and thereference substance.

As shown separately in FIG. 2, the detection substrate 30 has an upperside surface 50 which, in the assembled disk 10 of FIG. 1, faces towardthe reflection substrate 32. Rows of assay regions 52 extend radiallyacross the upper side surface 50, and are equally spaced apartcircumferentially around the upper side surface 50. Ligands 54 areprovided at each assay region 52 to hold the sample units 35 in placebetween the two substrates 30 and 32, as shown in FIG. 3. Specifically,the ligands 54 selected for the imaging process are known to bind,accept or otherwise capture a specific reference substance that theprocess seeks to detect in the sample units 35. These and other featuresof the disk 10 can be provided as described in U.S. Pat. No. 8,735,846,which is incorporated by reference, including fluidic channels 56 forconveying the sample units 35 to the ligands 54, and a protectivesubstrate 58.

The ligands 54 at each assay region 52 are arranged to provide a patternof binding and non-binding sites at the assay region 52. As shownpartially in FIG. 4, the arrangement of ligands 54 in this particularexample provides a uniformly repeating pattern of binding sites 60shaped as narrow linear areas. The binding sites 60 delineate acorresponding pattern of non-binding sites 62 which, in the givenexample, are shaped as triangles with sides at the surrounding bindingsites 60 and corners where the binding sites 60 intersect. Thedimensions of the binding and non-binding sites 60 and 62 are known andstored as baseline data for the imaging process.

As shown separately in FIG. 5, the reflection substrate 32 has a lowerside surface 70 that faces the detection substrate 30. The lower sidesurface 70 also has rows of assay regions 72. Each assay region 72 onthe reflection substrate 32 is located directly opposite an assay region52 on the detection substrate 30. Moreover, each assay region 72 on thereflection substrate 32 has reflective surface areas 74 (FIG. 6) withthe same triangular shape, size and pattern of arrangement as thenon-binding sites 62 (FIG. 4) on the detection substrate 30. Thereflective surface areas 74 are thus located coextensively opposite thenon-binding sites 62. Each assay region 72 on the lower side surface 70further has contiguous non-reflective surface areas 76 in anintersecting linear arrangement that matches and faces oppositely towardthe linear binding sites 60 on the opposed assay region 52. Like thedimensions of the binding and non-binding sites 60 and 62, thecorresponding dimensions of the reflective and non-reflective areas 74and 76 are known and stored as baseline data for the imaging process.

In operation, the system 20 performs the imaging process in a field ofview having the reflection substrate 32 as a background, as noted above.This can begin with a baseline image of the reflection substrate 32without any sample units 35, as shown in FIG. 6. Such a baseline imagemay serve as a reference for observing the position, size and/or shapeof sample units 35 on the same background in other images.

An image of the reflection substrate 32 with sample units 35 in theforeground may appear as shown partially in FIG. 7. As shown separatelyin FIG. 8, one such sample unit 35 is located entirely within areflective surface area 74. That sample unit 35 is likewise locatedentirely within the coextensively opposed non-binding site 62 (FIG. 9).Since the sample unit 35 is shown to have reached that location withoutbeing bound by the ligands 54 on the detection substrate 30, itsposition strongly suggest the absence of the reference substance in thissample unit 35. If this unbound position of the sample unit 35 is takenas a threshold indication of distinction from the reference substance,the sample unit may be dismissed as lacking the reference substance.

In the image shown partially in FIG. 10, a sample unit 35 is shown tooverlie a non-reflective surface area 76 on the reflection substrate 32,and to reach across adjacent triangular reflective surface areas 74.This sample unit 35 is thus shown to be bound to the detection substrate30 at the pattern of binding sites 60 provided by the ligands 54 (FIG.11), and to reach onto adjacent triangular non-binding sites 62. Suchbinding of the sample unit 35 to the ligands 54 indicates the presenceof the reference substance. Additionally, the shape of the sample unit35 may be observed directly, and its size may be observed by comparisonwith the known dimensions of the reflective and non-reflective surfaceareas 74 and 76. The degree of binding, the shape, and the size of thesample unit 35 can be compared with their known counterparts for thereference substance to assess the similarities or differences indicatedfor the sample unit 35 and the reference substance. If these comparisonssatisfy threshold requirements of similarity, the sample unit 35 may beaccepted as including the reference substance.

As an intermediate example, the image shown partially in FIG. 12includes a sample unit 35 with a lesser degree of binding with theligands 54, as compared with the example of FIG. 10. This is a lesserindication that the sample unit 35 includes the reference substance. Theshape of the sample unit 35 is the same, but the different size providesa correspondingly different comparison with the reference substance. Ifthese observations of bonding, shape and size are consideredinconclusive, the imaging process may proceed with spectral response asa parameter.

Specifically, an image of the sample unit 35 is formed with light in afirst band of wavelengths. In this example the image of FIG. 12 is takenas the image formed at the first band of wavelengths. The LCD panel 40can then be operated to emit light in a second band of wavelengthsdifferent from the first, and another image is then formed with thelight in the second band of wavelengths. This could be an image as shownin FIG. 13. A comparison of the images of FIGS. 12 and 13 shows that thesample unit 35 has greater reflectance and transmittance of light in thefirst band of wavelengths and greater absorption of light in the secondband of wavelengths. This difference in spectral response of the sampleunit is compared with a known difference in spectral response of thereference substance at the first and second bands of wavelengths. It isthen determined whether or not the detected difference in spectralresponse meets a predetermined threshold of identity with the knowndifference.

In an alternative example, instead of using differing bands ofwavelengths, light of only a single wavelength could be used for any oneor more of the multiple exposures performed in a spectral response stageof the method, as long as multiple exposures differ in wavelengthsufficiently to obtain a detectable difference in spectral response.

An additional feature of the disk 10 is shown in FIG. 5 where the lowerside surface 70 of the reflection substrate 32 has non-reflectiveregions 80 reaching fully between the rows of assay regions 72. As anon-reflecting region 80 on the rotating disk 10 moves across the pathof light shown in FIG. 1, it blocks the transmission of reflected lightfrom the disk 10 to the sensor array 46. This enables the method toinclude an intervening discharging step between the formation ofsuccessive images by effectively exposing the sensor array 46 todarkness so that the sensor elements can fully drain the chargesgenerated in one or more previous exposures to light reflected from thedisk 10.

This written description sets for the best mode of carrying out theinvention, and describes the invention so as to enable a person skilledin the art to make and use the invention, by presenting examples ofelements recited in the claims. The patentable scope of the invention isdefined by the claims, and may include other examples that occur tothose skilled in the art. Such other examples, which may be availableeither before or after the application filing date, are intended to bewithin the scope of the claims if they have elements that do not differfrom the literal language of the claims, or if they have equivalentelements with insubstantial differences from the literal language of theclaims.

What is claimed is:
 1. An apparatus comprising: a biosensor diskstructure including a first substrate with a first inner surface, asecond substrate with a second inner surface facing oppositely towardthe first inner surface, and fluidic channels reaching between the firstand second inner surfaces; wherein the first inner surface has bindingsites that each include a ligand selected to capture a referencesubstance and non-binding sites that are substantially free of theligand and that adjoin the binding sites, the first substrate istransparent at the non-binding sites, and the non-binding sites havediscrete polygonal configurations of equal size and shape; and thesecond inner surface has non-reflective areas and reflective areasbounded by the non-reflective areas, and the reflective areas havediscrete polygonal configurations sized and shaped equally with thenon-binding sites such that the reflective areas are locatedcoextensively opposite the non-binding sites.
 2. The apparatus of claim1, wherein the non-reflective areas are contiguous around and betweenthe reflective areas.
 3. The apparatus of claim 1, wherein thenon-reflective areas are sized and shaped equally with the binding sitesand the binding sites and non-reflective areas are located coextensivelyopposite one another.
 4. The apparatus of claim 1, wherein thenon-binding sites are bounded by the binding sites.
 5. The apparatus ofclaim 1, wherein the binding sites are contiguous around and between thenon-binding sites.
 6. The apparatus of claim 1, wherein the polygonalconfigurations are triangular.